Cannot cleanly build Qt from source (ApplicationManager error)

I cannot cleanly build the 6.8.0 RC sources (as delivered by the Maintenance Tool) according to the instructions in README.md. I get error messages relating to ApplicationManager, pasted below, during the CMake generation step.

The workaround is to pass -skip QtApplicationManager to configure, but most users will struggle to realize that they must do this.

...
-- Configuring done (379.9s)
CMake Error at qtapplicationmanager/cmake/QtAppManHelpers.cmake:37 (set_target_properties):
  Cannot find source file:    C:/Qt/6.8.0/Src/src/dbus-interfaces/io.qt.applicationmanager.xml
Call Stack (most recent call first):
  qtapplicationmanager/src/main-lib/CMakeLists.txt:61 (qtam_internal_add_dbus_adaptor)
CMake Error at qtbase/cmake/QtTargetHelpers.cmake:156 (target_sources):
  Cannot find source file:    C:/Qt/6.8.0/Src/src/dbus-interfaces/io.qt.applicationmanager.applicationinterface.xml
Call Stack (most recent call first):
  qtbase/cmake/QtModuleHelpers.cmake:609 (qt_internal_extend_target)
  qtapplicationmanager/src/application-main-lib/CMakeLists.txt:2 (qt_internal_add_module)
CMake Error at qtbase/cmake/QtTargetHelpers.cmake:156 (target_sources):
  Cannot find source file:    C:/Qt/6.8.0/Src/src/dbus-interfaces/io.qt.packagemanager.xml
Call Stack (most recent call first):
  qtapplicationmanager/src/tools/controller/CMakeLists.txt:17 (qt_internal_extend_target)
-- Generating done (69.3s)
CMake Generate step failed.  Build files cannot be regenerated correctly.
CMake Error at C:/Qt/6.8.0/Src/qtbase/cmake/QtProcessConfigureArgs.cmake:1131 (message):
  CMake exited with code 1.
CMake Error at C:/Qt/6.8.0/Src/cmake/QtIRProcessHelpers.cmake:173 (message):
  c:\Qt\6.8.0\Src/qtbase/configure.bat -top-level -prefix
  C:\Qt\6.8.0\msvc2022_64_BL -debug exited with status: 1
Call Stack (most recent call first):
  C:/Qt/6.8.0/Src/cmake/QtTopLevelHelpers.cmake:35 (qt_ir_execute_process_and_log_and_handle_error)
  C:/Qt/6.8.0/Src/cmake/QtTopLevelHelpers.cmake:57 (qt_tl_run_toplevel_configure)
  C:/Qt/6.8.0/Src/cmake/QtTopLevelConfigureScript.cmake:17 (qt_tl_run_main_script)